M1911 Colt Gauge Drawing for Slide Stop & Link Pin, Form Top of Thumb Piece, Original. From the collection of Colt collector and firearm designer, Richard Baker. Original gauge drawing dated Dec 14th & 15th, 1911. Drawing is original from Colt engineering department. Ink on bond paper (see photo with watermark). Size is 5x8 inches. Paper is strong and in good condition for its 112 year age. See pictures of front and back.